Fuel burner



Oct. 10, 1939. P. s. ARNOLD FUEL BURNER 3 Sheets-Sheet 1 Filed April 16,1934 INVENTOR.

PHILIP 5 ARNUL-D Oct. 10, 1939. P. s. ARNOLD FUEL BURNER Filed April 16,1934 3 Sheets-Sheet 2 INVENTOR. PHILIP 5.ARNDL:D.

ATTORNEY.

Oct. 10, 1939. P. s. ARNOLD FUEL BURNER 3 Sheets-Sheet 3 Filed April 16,1934 can 00 INVENTOR.

Pl-nmp S.ARN:1L.D.

ATTORNEY.

Patented Oct. 10, 1939 UNITED STATES PATENT OFFICE 7 Claims.

This invention relates to fuel burners, and the principal object of theinvention is to provide a burner operating upon a new principle ofcombustion, the burner construction and manner of introduction of thefuel and air for combustion being productive of a highly eflicientmethod of combustion of low grade liquid, or a solid or gaseous fuel.Preferably, my improved fuel burner comprises a chamber into the bottomof which fuel is injected in any of its convenient forms such as aliquid hydro-carbon or powdered combustible material and enough air isinjected into the fuel body to produce suilicient combustion to raisethe temperature of the remaining portion to above combustion temperatureand then passes into a zone wherein air is added at successive points ofits travel suflicient in volume to produce complete combustion.

A further object of the invention is to provide a combustion chamber inwhich the combustion is attained withoutreverberation. In the presentforms of combustion chambers or devices a reverberatory combustion isproduced due to the turbulence resulting from the non-uniform rate ofheat absorption through various parts of the fuel and air body. Thisinvention seeks to avoid turbulence of combustion and therefore secure aquiet high capacity combustion chamber for continuously burning any fuelcapable of a practical continuity in supply.

An additional object of the invention is to provide a new and uniqueburner structure positioned exteriorly of the furnace and including arefractory lined combustion chamber so constructed as to reduce thenoise of combustion therein to a minimum.

A further and primary object of the invention is to provide a combustionchamber of such construction that combustible gases introducedthereintopass spirally to a discharge opening,

the wall of the chamber having apertures for the admission of air atsuccessive spaced points to introduce air progressively into the gasesas they pass through the chamber.

A further object of the invention is to provide in a combustion chamberof the character described a construction tending to restrict therapidity of movement of the gases linearly through the chamber.

It is also an object of this invention to provide a combustion chamberhaving a nozzle connected with a fuel pipe or conduit for injection ofair, steam or gas and fuel into the chamber under pressure to causeatomization or separation of the fuel and to impart velocity thereto. a

valve for varying the flow of fuel in the fuel pipe per unit of time,and means for positioning the valve relative to its seat actuated bypressure of air in the air pipe and a temperature controlled means forvarying the pressure in the air pipe to thereby variably position thefuel valve relative to its seat and thus vary the flow of fuel and airper unit of time in the fuel pipe in accordance with temperature changein the area being heated.

Further features of the invention are involved in the construction ofthe parts for providing the air and fuel and the associated controldevices whereby a high efliciency is attained in opera tion coupled witha minimum expense of construction, all of which are hereinafter morefully described and claimed.

A preferred form of construction of an oil burner embodying my inventionincluding the arrangement of the burner in relation to a furnace of theordinary coal or wood burning type is shown in the accompanying drawingsin which- Fig. 1 is an elevation showing my improved burner as appliedto a domestic heating furnace. v Fig. 2 is an enlarged vertical sectionof the burner proper and the associated control devices.

Fig. 3 is a section of the combustion chamber taken on line 3-3 of Fig.2.

Fig. 4 is a section taken on line 4-4 of Fig. 2 showing the safetycontrol.

Fig. 5 is a section similar to that shown in Fig. 3 showing analternative form of construction of the combustion chamber at the pointof introduction of the fuel.

Fig. 6 is a similar view of another form of construction of thecombustion chamber.

Fig. '7 is a longitudinal section of a convenient form of atomizingnozzle.

Fig. 8 is an elevation partly in section showing an alternative form ofconstruction of a combustion chamber and its relationship to a domesticheating furnace.

Figs. 9 and 10 are sectional views of alternative forms of thecombustion chamber,

Fig. 11 is a vertical section of another form of combustion chamber.

Fig. 12 is a section taken on line 2l2 of Fig. 11.

Fig. 13 is a vertical section of a further modifled form of combustionchamber.

In Figs. 1 and 2 is shown a preferred form of the construction andarrangement of the burner and the means for supplying air and oil underpressure thereto, the burner being housed in the casing indicated at Iand to this casing is connected a conduit 2 opening to the exhaust flue3 of the furnace indicated generally at 4. A valve 5 is provided in theflue 3 which, when in the open position as shown in Fig. 2, directs thegases of combustion into the flue and into the radiator ring 6 orchamber of the furnace through which the gases of combustion usuallypass when used in the ordinary way in the burning of fuel and in myarrangement, these gases pass downward through the radiator, firepot,grate, ashpit, and thence out through an auxiliary flue I which is hereshown as discharging into the exhaust flue 3 adjacent the stack (notshown) in the wall I. The heating of these usual channels for heatedgases in a hot air furnace heats the air in the exterior shell of thefurnace and this heated air passes through the usual fiues 9, 9 to therooms of a building to be heated. The casing I having my improved burnermay be formed of any approved material, preferably metal, and theexterior thereof may have an insulating covering I particularly aboutthat portion thereof immediately surrounding the combustion chamber I Ito prevent material loss of heat to atmosphere.

The combustion chamber II is preferably formed of a refractory materialand the bottom section thereof, indicated at I2, is greater in diameterthan the body I3. The bottom wall of the chamber is provided with aseries of apertures I4 for inflow of air and the side walls of thebottom portion I 2 are provided with the tangential apertures I5. Thebody of the chamber above the bottom wall has apertures I6, preferablytangential, opening therethrough. There are also a series of air inletholes II at the open upper end ll of the combustion chamber II. This endI8 closes the interior of the casing I to the conduit 2 so that air inthe casing must pass into the combustion chamber to complete combustion.The flue 2, valve 5. and the walls of the tube 3 to the point ofentrance into the combustion chamber and channel 6 of the furnace arelined with a fire resistant material indicated at I9. To the bottom wallof the combustion chamber II and adjacent the nozzle 22 is connected afuel pipe having a valve 2| for control thereof to provide a pilotlight. Liquid or other form of fuel in atomized condition is dischargedthrough the nozzle 22 into the bottom section I 2 of the combustionchamber as shown in Fig. 3 from which it will be observed that theatomizing nozzle by discharging the fuel stream tangentially into thechambercauses the supplied fuel to pass circumferentially thereabout inorder that burned and/or unburned gases will partially or wholly envelopthe fuel Jet. This condition is enhanced by extending the wall of thechamber at the nozzle aperture inwardly of the circumference to providea shield for the nozzle as indicated in Fig. 3 and preventing contact offree air with the let.

The atomizing nozzle is shown generally in Fig. 7 and is a common formof structure having an exterior shell 24 through which air under highpressure is fed from the pipe 25 and within this member 24 is theterminal portion 26 of the oil supply pipe 21. The discharge end 23 ofthe pipe 2! is of a smaller diameter and terminates at the opening 29 ofthe shell 24 through which air flows parallel to the end of this tubeand past the button 30 to produce spray. This is a common form ofatomizing nozzle and other forms of nozzles adapted for the purpose maybe utilized if desired without departing from the spirit of thisinvention.

In the form of construction of the bottom section of the combustionchamber shown in Fig. 5. a single nozzle 22 may be employed dischargingcentrally between two circular portions providing chambers 3| and 3|. Inthe construction shown in Fig. 5, the wall of the chamber opposite thenozzle has the inwardly extending point or portion 33 with curved sidewalls and at the nozzle has similar curved portions of the wallthereabout. The inwardly projecting portion 33 divides the fuel and airstream causing the same to circulate in opposite directions around thechambers 3i and 3i and the curved portions at the nozzle deflect the airand fuel stream from direct contact with the nozzle end and thus shieldthe nozzle from the rotating gases. In either of these chambers shownand in any form of the combustion chamber the apertures I5 for inflow ofair into the fuel stream should extend practically tangentially throughthe wall or at least at a material angle to a radial line of thecircular chamber and in a direction to permit air to pass into thechamber in approximately the direction of flow of fuel discharged by thenozzle.

Thus the inflow of air tends to accentuate the rotation of the gaseousbody in combustion and preferably in any of the constructions of thecombustion chamber shown, the wall, as the wall 34 shown in Fig. 2,between the body and the bottom sectionor chamber I 2, is inclined or soconstructed as to tend to delay movement of the gases in combustionaxially through the body of the burner. Ignition of the fuel takes placein this bottom section and theinflowing fuel body is raised intemperature to above the combustion temperature. To continue thecombustion, the openings I6 are provided in the body in order todischarge air into the gases in passing upwardly toward the exhaust fiue3 of the furnace. Air passing through these apertures I4, I5, I6 and IIin the form of combustion chamber shown in Fig. 2 is provided by a fan35 which is positioned above a dividing wall 36 in the casing I andtakes its supply through an aperture 31 opening to the lower chamber 33of the member I. The chamber 38 is open at its bottom to atmospherethrough a conduit 39 having a valve 40 for varying the area of theopening, the control of which is hereinafter described. The fan 35 isdriven by a motor 4I supported on a base 42 suspended from the dividingwall 36 by the studs 43.

For supplying air under pressure to the nozzle, I provide a two-cylindercompressor supported from the base 42 on which the motor is mounted andthis apparatus consists of a casing providing a chamber 44 containingoil for lubrication purposes and the compressor consists of the twooutwardly disposed cylinders 45 and 46 and companion pistons operatedalternately by any approved means as an eccentric 41 on the motor shaft.

The said shaft has a bearing in a central column 48 in the chamber 44and the column has an aperture 49 opening into the chamber below the 011surface and leading upwards to the bearing for the motor shaft. Thepistons have the usual spring valve 50 in the outer end which opens onthe instroke of the piston and closes on the outgoing stroke and thehead of the cylinders is formed with an aperture 5| covered by arecessed plate 52. An aperture 53 is provided from the recess of thisplate to the interior of the chamber 44. Thus the air is taken from theinterior 3. of the casing i in which the compressor is mounted throughthe motor ll and through apertures ll in the base 42 and is dischargedinto the chamber 44 and thus the oil in the said chamber is underpressure and is caused to lubricate the bearing for the motor andcompressor. This oil under pressure may, by a conduit, (not shown) leadto any part of the apparatus which requires to be oiled.

The chamber 44 acts as a storage tank for air under pressure and the airline 25 has its intake end in this chamber above the oil surface andupturned as shown to prevent any material amount of oil entering thesame. As before described, the air line 25 opens to the nozzle as shownin Fig. 7. The oil line 21 has a constant level chamber 54 and leads tothe atomizer or nozzle as indicated in Fig. 7. The compressor may be ofany type providing for substantially constant air pressure.

The control of the burner in operation is accomplished by the followingdescribed mechanism:

Connected into the fuel pipe 21 is a control valve 55 and this valve hasa stem 56 connected to a lever 51 hinged at one end to a diaphragmcasing 55 and the opposite end of the lever 51 is connected by means ofa lever 55 with the valve 4|] controlling the air inlet to the casingthrough which the fan is supplied. The lever 51 has a spring 60 tendingto close the fuel valve 55 and also to restrict the air opening throughthe turning of the air valve 40. The lever also has a bearing 5lopposite the pivotal connection with the oil valve stem 56 engaging theflexible diaphragm 6i forming one wall of the casing 56. The chamber ofthe casing 58 is connected to the air line 25 by a pipe 58 through whichair under pressure is supplied to automatically open the valve andpermit flow of 011. Thus it will be observed that the oil valve 55 andthe valve or .shutter may both be operated or adjusted in unison and theproper proportion of the air and oil are admitted to the combustionchamber II for accomplishing complete combustion. The construction shownin Fig. 2 is an arrangement adapted for use with oil or gas as a fuel.With a powdered fuel some change in construction of the valve would berequired but the relationship of the parts would be substantially thesame.

The compressor preferably has a constant output greater than is requiredby the atomizing nozzle or nozzles and to control the operation of theburner, I provide a thermostat, indicated generally at 62, which may belocated at any convenient point of the building or space to be heated.The thermostat consists of a bimetal helix 63 for operating a needlevalve 64 normally closing the opening to a conduit 65 connected with theair line 25 here shown as being connected to the line 25 through theconduit 58' for the diaphragm chamber. Due to an excess temperature inthe heated space the thermostat opens the conduit 65 permitting escapeof air, thereby reducing the pressure in the diaphragm chamber 58permitting the lever to act under tension of the spring 60 to partiallyclose the valve 55. Under the opposite condition, that is, a reductionin temperature of the heated space, the helix operates to close theneedle valve 64 which tends to build up the pressure in the diaphragmchamber thereby opening the fuel valve 55 to a greater extent and alsoopening the valve or shutter at 40 to increase the air flow to the fan35 and thus increasing the heat output of the burner.

There is an additional safety control shown generally at 66. This, asshown in Figs. 2 and 4, consists of a bimetal helix 55' mounted rigidlyat one end on the end of a tube 61 which is screwed into an apertureprovided in the radiator ring or channel 6 of the furnace and attachedto the inner end of the helix and'extending out through the tube 61 is ashaft 56 on the outer end of which is mounted a disc 65 having a notchII in its periphery.

When the temperature of the helix is not increased by combustion gasespassing through the radiator ring from the combustion chamber H the discrests in such a position that a pin II mounted on the end of a pivotedlever 12 is held in the notch by tension of the spring 11. The lower endof the lever 12 is connected by a link 13 with a needle valve ll havinga stem riding in a guide 15. The valve may seat in the end of the tube16 connected with the air supply pipe 1 56' and thence with the main airsupply pipe 25. The toggle structure consisting of the lever I2 and link15, is so arranged that when the pin ll rests in the notch in the disc65, the needle valve 14 is open.

If at any time the fire in the combustion chamber goes out, the helix inthe radiator ring is allowed to cool and thus rotate the disc 65 tobring the notch 10 opposite the pin permitting the lever to be moved bya spring 11 to open the valve 14 releasing the air pressure and closingthe fuel valve. Flow of raw oil into the combustion chamber is thusprevented.

To start the burner, the lever 12 may be manually held in the positionshown in Fig. 2 with the valve I4 closed. This causes a rise of pressurewithin the air supply pipe through operation of the motor and compressorwhich is understood to be in operation at the time and the consequentdeflection of the diaphragm 6| to the position shown in Fig. 2 opens thefuel valve. After the fire has been burning a short time the helix inthe furnace radiator ring 6, which has become heated, rotates the discso that the lever upon release by the operator has the pin H restingupon the periphery of the disc thereby holding the. needle valve 14closed and the fuel valve 55 open permitting the burner to continue inoperation.

It is to be seen from the foregoing that there are preferably twoinstrumentalities for controlling the oil burner, one consisting of thethermostat structure 62 for varying the rate of consumption of oil tocorrespond with the temperature changes in the room being heated, andthe other consisting of the safety control 66 both of which operatethrough a release of air pressure in the air supply pipe connected tothe nozzle or nozzles. The room thermostat structure 62 and capacity ofthe port controlled by the needle valve 64 is such as to reduce thepressure but not to such extent as to quickly or fully close the fuelvalve and its operation is therefore to control the burner in the amountof fuel consumption while the structure indicated generally at 66 isadapted to cause complete cessation of the fuel flow.

It will be observed that in the event of breakdown of the oil burnerstructure and necessity for continued use of the furnace throughconsumption of fuel within the furnace itself, the valve 5 in theexhaust flue 3 is closed and a valve TI in the flue I is closed. Thispermits the furnace to be operated in the usual way with the fire in thegrate indicated by the dotted line II and the products of combustionwill pass out through the usual exhaust conduit I. Under this condition,the valve plate 5 prevents soot or dust from entering the oil burnerchamber. When used with the oil burner the valve 5 is open and the valveTI is also open so that the products of combustion pass through theradiator ring 6 downward through the furnace and out through. the flueI.

The combustion chamber itself constitutes one of the primary features ofthis invention, namely, a chamber of fire resistant material into whichoil is discharged tangentially and to which air is progressivelyprovided through apertures therein as the combustible products passlinearly through the chamber to finally discharge into the furnace. Theinvention is not confined to the use of a combustion chamber as shown inFigs. 1 and 2. An equivalent arrangement is indicated in Fig. 8 wherethe burner proper con sists of the shell Il of refractory materialplaced in the ash pit.

The oil nozzle 19 leads tangentially with the shell 18' in the samemanner as the nozzle 22 of the burner shown in Fig. l. The open upperend of the shell ll discharges up through the normal combustion chamberand the usual radiator ring 6 of the furnace to the exhaust, flue 3'.Air may be provided by means of. a fan and motor therefor indicated atl! and while I have not shown the motors etc., for provision of oil andair in atomization of the fuel, apparatus such as is described inconjunction with the structure shown in Figs. 1 and 2 may be employed.Although not shown, this burner structure 18 is provided with a pilotlight as shown with burners previously described. The combustion chambermay also be made as shown in Fig. 9 and may be made of a metal wall llon the exterior of the refractory wall 82 and a nozzle is shown at I!entering the lower portion of the combustion chamber which is providedwith a ledge 84 to prevent too quick a rise of the combustible gasesinto the main body of the burner.

Another convenient'form is shown in Fig. 10, which is preferablyconical, having the tapered walls 85 of the same character andconstruction as shown in Fig. 9 and the lower end of greater diameterthan the open discharge end It. This tapered inwardly inclined walltends to delay passage of the gases until combustion has beenpractically completed within the chamber and in either of the combustionchambers shown the nozzles lead thereinto to cause rotational movementof the gasified elements and the smothering of the fuel jet.

In Figs. 11 and 12 is shown a different form of chamber, the principalfeature of which is a construction providing for entry of air forcombustion centrally of the rotating bodies of the gases in combustion.This arrangement is a useful form and is particularly useful where theburner shell III is of large diameter. The casing has a re-entrantportion llll open at the bottom for flow of air thereinto and has itswalls provided with tangential apertures ill! for causing air to flowinto the fuel body in the same direction as the outer tangentialapertures ID! in the main shell. In all forms of combustion chamberscarbon accumulation is prevented by the layer of air introduced betweenthe flame and chamber wall.

The re-entrantportion extends centrally into the chamber and hasopenings I in the top thereof to provide additional air to the center ofthe gases of combustion as they pass into the outlet I 05. With arotating body of the gases and air entering only from the exterior ofthe gaseous body, the central portion does not in some cases receivesufficient air for combustion or at least for complete combustion by thetime the gases pass from the chamber and this, of course, varies withthe diameter of the body of the rotating gases. By the arrangementshown, the gaseous body is provided with air in the interior as well asthe exterior thereof. In Fig. 13 is shown another convenient form ofchamber in which the fuel is discharged in the bottomi chamber I06 andignited as in the other cases described. The walls of the combustionchamber above the chamber I08 are outwardly inclined so that thediameter of the chamber increases toward the outlet llil. By thisarrangement there is a greatly increasing quantity of air dischargedinto the gases as they rise to the outlet. The diameter of the outletbeing less than the diameter of the chamber, the volume of flow of theburning gases per unit of time from the chamber is restricted.

By the construction of the combustion chamber hereinbefore described andparticularly by the constructions shown more fully in Figs. 1 and 2, acomplete burner outfit may be installed in con- Junction with anordinary wood or coal burning heating furnace without removal of any ofthe usual furnace parts leaving it all in normal state. The installationmay be made at very little cost, it being only necessary to provide theflue I open to the ash pit of the furnace and to the exhaust flue 3 ofthe furnace to which the discharge flue 2 of the combustion chamber isconnected and also to provide a threaded opening in the radiator ring orcorrespondingly similar structure of the furnace for introduction of thesafety trip 66. The burner may thus be completely set up in all itsrelationship of parts even including the trip 68 at the factory andpractically adjusted prior to installation and thus upon installationand connection of the thermostat G2 and air supply pipe therefor and theoil supply pipe the installation is completed and ready for operation.

The combustion chamber forming the principal feature of this inventionis not restricted to use with any specific type of furnace constructionand may be used in any way that may be found desirable where a completecombustion of gases is desired. The burner may be used in the productionof heat for any purpose and, as before stated, the invention is not onlyin the construction of the combustion chamber and the associated fuelsupply pipes etc., but exists fundamentally in the method by which thefuel is progressively burned in passing through the chamber. In so faras this feature is concerned, the fuel may be of various forms in whichit is first brought to a temperature above combustion temperature andgiven a rotary motion and passes linearly or outwardly through thechamber during which air for combustion is added as the gases passprogressively through the chamber. The air may be introduced to theexterior of the rotating body only or to both the exterior and.interiorthereof and in the same direction as the body of gases is rotating toincrease the rapidity of rotation. By this method of burning a veryquiet combustion is attained. This quietness is due firstly to theexcess of fuel over air and next to the fact that the fuel jet issurrounded by combustion gases and gasified fuel which presents contactof the free air with the jet and thirdly to the fact that the air isadmitted in small streams to the gasifled and heated fuel that aredistributed over a comparatively large area and therefore I do notsecure a successive ignition within the mixture or a periodic portionalheating of the mixture and thus avoid flame noises which are produced inother types of burners through the individual combustion of portions ofthe combustible mixture which reach ignition temperature at differenttime periods.

Thus while I have herein described a specific use of my improvedcombustion chamber, the invention is not confined to such use as thecombustion chamber need not of necessity be positioned with itslongitudinal axis in vertical position as is the desired arrangement inthe use of the burner illustrated. The invention therefore broadly isinvolved in the combustion chamber and the manner in which combustiontakes place.

From the foregoing description it is believed evident that the variousobjects of the invention are attained by the structures described, andthat a comparative simple and economic construction is secured.

Having thus described my invention, its utility and mode of operation,what I claim and desire to secure by Letters Patent of the UnitedStates 1. In an oil burner, a combustion chamber havingvertical sidewalls of refractory material, a bottom, and an open top, the verticalwalls of the chamber being provided with tangential openings, a nozzledischargingv tangentially into the chamber adjacent the bottom, meansfor supplying a combustible mixture of hydro-carbon fuel and air underpressure to the nozzle, a pilot burner at the bottom of the chamber forigniting the combustible mixture as it passes into the chamber, andmeans for discharging air in desired volume through the said tangentialopenings into the combustible mixture in the combustion chamber, saidtangential openings providing for addition of air to the combustiblemixture at successive points in its path of movement through thecombustion chamber whereby combustion is completed prior to passage ofthe fuel in combustion through the open top of the chamber.

2. In an oil burner, a hollow member provid ing a combustion chamberhaving a bottom and an opening thereabove for movement of gases ofcombustion vertically therethrough, the chamber being of greatestdiameter at the bottom, the body of the chamber above the bottom beingof less diameter and the opening being less in diameter thanthe-diameter of the body providing a restriction to flow of gasesthrough the chamber, the wall of the chamber above the bottom beingprovided with tangential openings arranged thereabout in successivehorizontal planes from near the bottom to near the top, means fordischarging air through the said tangential openings into the chamber, anozzle discharging tangentially into the combustion chamber adjacent itsbottom, means for supplying a combustible oil and air mixture to thenozzle, and means for igniting the combustible mixture as it enters thechamber, the tangential flow of said mixture and of air discharging intothe combustion chamber causing the gases in combustion to flow in arotating stream through the combustion chamber.

3. In an oil burner, a vertically positioned chambered member formed ofa refractory material having a bottom wall provided with openings, sidewalls, and an open top, a nozzle discharging tangentially into thechamber adjacent the bottom wall, means for supplying air and liquidhydro-carbon fuel through the nozzle whereby a whirling mass of fuel andair is provided in the chamber, a pilot light approximately at thecenter of the bottom wall, the body of the chamber at a comparativelyshort distance above the bottom wall being of less diameter than at thepoint of introduction of the fuel and air providing a means for delayingthe movement of combustible gases through the chamber, the side walls ofthe said chamber adjacent the bottom being provided with a series ofopenings through which air may pass into the fuel and air stream in thedirection of its travel and further being provided with a plurality ofseries of openings in vertically spaced relation in the body thereofabove the said bottom portion for passage of air into the chamberwhereby air is added to the gases as they pass upwardly to the open top.

4. In an oil burner, a combustion chamber having a bottom wall and adischarge opening thereabove, said chamber having cylindrical bottom andupper sections, the upper section being of less diameter than the bottomsection and greater in diameter than the discharge opening providing astructure tending to cause a slow movement of the gases in passingtherethrough, means for discharging a fuel and air mixture tangentiallyinto the bottom section, means in the bottom section for igniting thefuel mixture, the wall of both the bottom and upper sections beingprovided with openings for discharging air tangentially into the fueland air mixture and maintaining the same in a rotating state in itspassage toward the discharge opening, the tangential openings in thewall of the upper section being so spaced that air is discharged intothe fuel and air mixture ';at successive points in its path of movementthrough the combustion chamber and combustion completed prior to flow ofthe gases through the discharge opening.

5. In an oil burner, a vertically positioned chambered member ofrefractory material having a bottom and an opening at the top, the wallof the chambered member being provided with a plurality of series ofapertures in vertically spaced relation opening to the interior of thesaid chambered member between the bottom and top, a hollow casing withinwhich the chambered member is positioned, a discharge conduit at the topof the said casing, the interior of the easing being sealed from thesaid discharge conduit and the open end of the chambered memberdischarging thereinto, a nozzle for discharge of liquid fuel in atomizedform tangentially into the chambered member adjacent the bottom, meansfor supplying fuel to the said nozzle, and a controllable meanspermitting air to flow to the interior of the casing to pass through theapertures of the chambered member.

6. In an oil burner, a casing, a conduit at the upper end of the casing,a chambered member of refractory material within the casing and spacedtherefrom, said chambered member having a bottom, vertical side wallsand an opening at the top discharging to the said conduit, saidchambered member being provided with a plurality of series of verticallyspaced openings in its vertical walls through which air from theinterior of the casing may pass into the chambered member, a fuel pipefor discharging fuel into the chambered member adjacent its bottom, afan for forcing air into the casing for discharge into the chamberedmember through the openings in its vertical walls, and means for varyingthe volume 01 air and fuel flowing into the chambered member per unit ortime. 7

'1. In an oil burner, a member providing for a combustion chamberhavinga bottom, vertical side walls and a discharge opening at the top,the sidewalls of the member from the bottom to near the top beingprovided with a plurality of series of tangential openings in diflerenthorizontal planes, means for discharging air through the said tangentialopenings into the combustion chamber, a nozzle positioned to dischargetangentially into the chamber at the bottom, means for supplying acombustible oil and air mixture to the nozzle, and means for ignitingthe combustible mixture at the bottom oi. the chamber.

PHILIP S. ARNOLD.

